The diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other disorders has long been an area of intense investigation. Non-invasive methods for examining tissue include palpation, X-ray, MRI, CT, and ultrasound imaging. When the physician suspects that a tissue may contain cancerous cells, a biopsy may be done using either an open procedure or a percutaneous procedure. For an open procedure, a scalpel is used by the surgeon to create a large incision in the tissue in order to provide direct viewing and access to the tissue mass of interest. The entire mass (excisional biopsy) or a part of the mass (incisional biopsy) may then be removed. For a percutaneous biopsy, a needle-like instrument is used through a very small incision to access the tissue mass of interest and to obtain a tissue sample for later examination and analysis. The advantages of the percutaneous method as compared to the open method may be significant and may include: less recovery time for the patient, less pain, less surgical time, lower cost, and less disfigurement of the patient's anatomy. Use of the percutaneous method in combination with imaging devices such as X-ray and ultrasound has resulted in highly reliable diagnoses and treatments.
Generally there are two ways to obtain percutaneously a portion of tissue from within the body, by aspiration or by core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into pieces small enough to be withdrawn in a fluid medium. The method is less intrusive than other known sampling techniques, but one can only examine cells in the liquid (cytology) and not the cells and the structure (pathology). In core biopsy, a core or fragment of tissue is obtained for histologic examination which may be done via a frozen or paraffin section.
The type of biopsy used depends mainly on various factors present in the patient, and no single procedure is ideal for all cases. Core biopsy, however, is very useful in a number of conditions and is widely used by physicians.
A number of biopsy devices have been designed and commercialized for use in combination with imaging devices. One such biopsy instrument is the BIOPTY gun, available from C.R. Bard, Inc. and described in U.S. Pat. Nos. 4,699,154 and 4,944,308 as well as in U.S. Reissued Pat. No. Re. 34,056. The BIOPTY gun is a core sampling biopsy device in which the biopsy needle is spring-powered. However, when using the BIOPTY gun, the breast or organ must be punctured and the device is re-inserted each time a sample is taken. Another core biopsy device is the TRUE CUT needle manufactured by Travenol Laboratories. This TRUECUT needle collects a single core of tissue using a pointed element with a side-facing notch to receive tissue and an outer, sharpened sliding cannula to cut the core sample from the surrounding tissue.
Aspiration biopsy devices for obtaining biopsy samples from the body are described in the following: U.S. Pat. No. 5,492,130; U.S. Pat. No. 5,526,821; U.S. Pat. No. 5,429,138; and U.S. Pat. No. 5,027,827. These patents describe devices which use the aspiration method of liquid suspended tissue extraction rather than core sampling to extract tissue.
To overcome operator error associated with such devices, and to enable multiple sampling of the tissue without having to reenter the tissue for each sample, a biopsy instrument now marketed under the tradenamne MAMMOTOME was developed. Embodiments of the invention are described in U.S. Pat. No. 5,526,822. The MAMMOTOME instrument is a type of image-guided, percutaneous, coring, breast biopsy instrument. It is vacuum-assisted and some of the steps for retrieving the tissue samples have been automated. The physician uses this device to capture "actively" (using the vacuum) the tissue prior to severing it from the body. This allows for sampling tissues of varying hardness. In the MAMMOTOME biopsy instrument, the cutter is rotated using a motor drive mounted in the instrument while the surgeon manually moves the cutter back and forth by a knob on the outside of the instrument. Thus, the surgeon is able, through tactile feedback, to determine whether the blade is effectively cutting tissue or if there is a problem, such as binding or stalling. The surgeon may then adjust the speed at which the blade is moved through the tissue, stop the blade, or back the blade away from the tissue. The device can also be used to collect multiple samples in numerous positions about its longitudinal axis, without removing the biopsy needle from the body. These features allow for substantial sampling of large lesions and complete removal of small ones. In the MAMMOTOME, a vacuum chamber is attached alongside and fluidly connected to an elongated, hollow piercer. The vacuum supplied through the vacuum chamber pulls tissue into the lateral receiving port of the hollow piercer.
For breast biopsies, the devices described so far are most commonly used in combination with either X-ray or ultrasound imaging to locate suspicious tissue, although other imaging modalities such as magnetic resonance imaging are also available. When using, for example, the MAMMOTOME biopsy device with an X-ray stereotactic table, the biopsy device is attached to a movable, mechanical mounting arm. The patient lies face down on the table and the patient's breast is guided through an opening in the stereotactic table. Several X-ray images of the breast are taken from different angles to determine the location of the calcifications, lesions, etc. which are to be removed from the breast. Next the mounting arm is manually repositioned so that the biopsy device is properly aligned with the breast. Then the mounting arm is manipulated to push piercer of the biopsy device into the breast until the tip of the piercer is positioned alongside the tissue to be sampled. Additional X-ray images are then made to confirm that the port on the distal end of the piercer is in the proper position to collect the desired tissue portions. The biopsy device is then used to retrieve one or more core samples of tissue. Additional X-ray images are taken to confirm the removal of the suspect tissue. Sometimes the biopsy device and mounting arm must be repositioned during the procedure so that the tip of the piercing element is in a new location in order to retrieve more tissue samples. As this brief description illustrates, there are many time consuming steps in getting the biopsy device properly positioned to retrieve the desired tissue. In addition, the accessibility of certain parts of the breast may be hindered by the degrees of freedom of the movement of the mounting arm. Also, the size of the stereotactic table and associated equipment precludes portability of the system. It is not possible, for example, to have a number of patients being prepared for the procedure in separate rooms of a clinic, if there is only one room set-up for doing the procedure. Having a portable system would allow the surgeon to go from room-to-room and perform the procedure, and thus allow more patients to be treated in a given time period at the clinic.
Biopsy devices are also used with other kinds of X-ray imaging systems such as those for which the patient is upright rather than lying down. The numerous steps described above for locating, confirming, and reconfirming using X-ray stereo "snapshots" are also necessary for the upright versions.
The MAMMOTOME biopsy instrument may also be used with real time handheld imaging devices such as ultrasound imaging devices. When using a biopsy instrument such as the MAMMOTOME with a handheld ultrasound imaging device, the surgeon gains the advantage of having real time imaging of the tissue of interest. Typically the ultrasound imaging device is held in one hand and pointed at the tissue being penetrated by the piercer. In order to facilitate positioning and manipulation of both the biopsy instrument and the imaging device, it is normally necessary to attach the biopsy instrument to a mechanical, articulating arm which is designed to support the weight of the biopsy instrument. In addition, since axial movement of the cutter on the MAMMOTOME is actuated by hand, the biopsy device must be rigidly supported to allow the surgeon to actuate the cutter without moving the tip. Alternatively, an assistant may be used to help operate the controls for the biopsy device. It would, therefore, be advantageous to design a handheld core sampling biopsy instrument wherein the cutter of the instrument was moved using a motor drive which could be actuated by the touch of a switch. Further, since some of the electrical and vacuum controls are not on the MAMMOTOME biopsy instrument itself, the biopsy instrument must be rigidly supported or the surgeon must have an assistant to actuate the controls. It would, therefore, be further advantageous if the electrical and vacuum controls for the biopsy device were positioned in relatively close proximity either on the instrument or, for example, on an associated generator. Automating axial movement of the cutter will, to some extent, eliminate the tactile feedback that the surgeon gets from moving the cutter blade manually. It would, therefore, be advantageous to provide a method of automatically measuring and controlling the axial movement of the cutter which could be utilized to, for example, prevent the cutter from advancing when the port is blocked.
In recent years several patents have issued describing handheld, motorized devices for the extraction of tissue from the body. Many of these devices are for arthroscopic surgery and are not intended for retrieving biopsy core samples of tissue for pathological analysis. The motors are for rotationally driving the cutting/milling end effectors, but not for advancing the end effectors into the tissue. Examples of arthroscopic, handheld, motorized devices include the following U.S. Pat. Nos. 4,995,877; 4,705,038; 5,192,292; 5,112,299; 5,437,630; 5,690,660; and 5,320,635.
In U.S. Pat. No. 4,940,061 issued to Terwilliger, et al, on Jul. 10, 1990, a core sampling, handheld biopsy deviceincorporating a battery powered motor for driving a means to penetrate and sever tissue is described. The motor axially drives a cutter to advance the cutter into tissue, thus eliminating the noise and jerking associated with mechanical stops of the spring-actuated devices. This significantly adds to the comfort of both the patient and the surgeon. However, the device does not incorporate a vacuum source for obtaining the tissue portion. As described in Burbank, et al, '822 and '333, the vacuum greatly facilitates the capturing of a complete tissue portion within the distal end port on the piercing element. Capturing more tissue with each sample reduces the number of samples required, and increases the likelihood of obtaining the diseased tissue. The Terwilliger device in '061 also does not address how to minimize leakage and spilling of the high volume of fluids present in biopsy procedures.
The surgeon may prefer to use an X-ray imaging system for some patients, and an ultrasound imager for others. In such situations, it would be desirable to use a biopsy instrument which is adaptable to both kinds of imaging systems.
Such an instrument could be used as a handheld instrument or also as an instrument mounted onto the arm of an X-ray stereotactic table, depending on the situation.
It is therefore desirable to provide a more versatile and "patient friendly" biopsy device than what is currently available. The device should be particularly adapted for use without mounting to an X-ray stereotactic table. It should be a lightweight, maneuverable, handheld device, so that the surgeon may have the option to perform the biopsy procedure in combination with an ultrasound imaging device. It is desirable that the device be easily transported from room-to-room so that several patients may be prepared for the surgical procedure concurrently, thus allowing more patients to be treated in a given time period, and potentially reducing the overall cost of the surgical procedure. In addition, it is desirable to perform a biopsy with fewer steps in order to decrease the overall time of the procedure. This would be achievable by eliminating the need to set-up and operate the X-ray stereotactic table. The combination of these factors could allow the surgical procedure to be more widely available to patients than it is currently.
It is also desirable to provide a handheld biopsy device which may be held parallel to the chest wall of the patient, so that suspect tissue masses close to the chest wall can be easily sampled. It is desirable that the surgeon be able to easily steer the penetrating tip of the handheld device towards the desired tissue to be sampled. It is further desired that the surgeon have tactile feedback as the tissue is probed by the penetrating tip of the device, to provide the surgeon with clues regarding the disease state of the tissue encountered. It is also desirable that the biopsy device be "patient friendly" by not having noisy or jerky mechanical actuations during the procedure, and by not having to be used with large machines such as an X-ray stereotactic table.